Chapter 12 Visual Summary

Population studies find that psychiatric disorders are prevalent in modern society. Studies of families, twins, and adoptees demonstrate a strong role of genetic factors in schizophrenia. Rather than a single gene determining whether a person will develop schizophrenia, several genes contribute to the risk. Review Figure 12.1 and Figure 12.2, Table 12.1, Animation 12.2

Structural changes in the brains of people with schizophrenia—including enlarged ventricles—may arise from early developmental problems. The emergence of schizophrenia depends on the interaction of genes that make a person vulnerable to environmental stressors. Review Figure 12.3, Figure 12.4, Figure 12.5, Figure 12.6, Figure 12.7, Figure 12.8

The frontal lobes are less active in people with schizophrenia than in people without it. Biochemical theories of schizophrenia emphasize the importance of the dopamine, glutamate, and serotonin receptors. First-generation antipsychotics block dopamine D2 receptors, while second-generation antipsychotics block serotonin 5-HT2A receptors in addition to acting on dopamine receptors. Review Figure 12.9, Figure 12.10, Figure 12.11, Figure 12.12, Box 12.1, Video 12.3

Depression also has a strong genetic factor. Serotonin has been implicated in this disorder. In general, females are more likely than males to suffer from depression. People suffering from depression show increased activity in the frontal cortex and the amygdala, as well as disrupted sleep patterns. Review Figure 12.13, Figure 12.14, Figure 12.15, Figure 12.16

There is considerable evidence that suicide is often an impulsive act, so intervening in cases of people showing the warning signs of suicide can save lives. Review Table 12.2

The most effective treatment for most cases of depression is a combination of cognitive behavioral therapy (CBT) and a selective serotonin reuptake inhibitor (SSRI). Review Table 12.3

Bipolar disorder is characterized by extreme mood swings and subtle changes in the brain, and it has a complex genetic component. The disorder is commonly treated with lithium. Review Figure 12.17

Anxiety states are characterized by functional changes in the temporal lobes, particularly the amygdala. Benzodiazepines, a type of anxiolytic (antianxiety drug), enhance the inhibitory effects of receptors for the transmitter GABA. Drugs affecting serotonergic synapses may also reduce anxiety. Review Figure 12.18

Post-traumatic stress disorder (PTSD) is characterized by an inability to forget horrible experiences. Temporal lobe atrophy in this disorder may be caused by chronic exposure to stress hormones. Review Figure 12.19

Obsessive-compulsive disorder (OCD) is characterized by changes in basal ganglia and frontal cortex and linked to serotonin. A restricted type of neurosurgery is sometimes used to treat the most severe cases of anxiety disorders. In Tourette's syndrome, overstimulation of dopamine receptors induces motor and verbal tics and compulsions. Review Figure 12.20, Table 12.4, Box 12.2, Activity 12.1

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